Vehicle control device

Abstract

A vehicle control device to be installed in a vehicle includes a self-driving controller and a calculator. The self-driving controller is configured to set a target vehicle speed and a target steering angle to allow the vehicle to trace a predetermined target travel locus. The self-driving controller is configured to control the vehicle based on the target vehicle speed and the target steering angle. The calculator is configured to calculate a deviation between an index of an actual vehicle behavior and an index of a reference vehicle behavior. The self-driving controller corrects one or both of the target vehicle speed and the target steering angle in accordance with an increase of the deviation, so as to stabilize the vehicle.

The invention claimed is: 
     
       1. A vehicle control device to be installed in a vehicle, the vehicle control device comprising:
 a self-driving controller configured to 
 set a target vehicle speed and a target steering angle to allow the vehicle to trace a predetermined target travel locus, and 
 control the vehicle based on the target vehicle speed and the target steering angle; 
 a calculator configured to calculate a deviation between an index of an actual vehicle behavior and an index of a reference vehicle behavior; and 
 a detector configured to detect a turning state of the vehicle, 
 wherein the self-driving controller corrects one or both of the target vehicle speed and the target steering angle in accordance with an increase of the deviation, so as to stabilize the vehicle, 
 wherein the self-driving controller completes the correction in accordance with completion of the turning state, and 
 wherein when completing the correction, the self-driving controller restores one or both of the target vehicle speed and the target steering angle to a value before the correction, using a low change speed relative to speed in normal time. 
 
     
     
       2. The vehicle control device according to  claim 1 , wherein the calculator
 sets, as the index of the reference vehicle behavior, a yaw rate calculated based on the target vehicle speed and the target steering angle, and 
 sets an actual yaw rate of the vehicle as the index of the actual vehicle behavior. 
 
     
     
       3. The vehicle control device according to  claim 2 , further comprising:
 a behavior controller configured to, upon detection of understeer behavior or oversteer behavior of the vehicle, perform behavior stabilization control to generate a difference in braking or driving force between a left wheel and a right wheel so as to generate a yaw moment to eliminate the understeer behavior or the oversteer behavior of the vehicle, wherein 
 the self-driving controller performs the correction after the behavior controller performs the behavior stabilization control. 
 
     
     
       4. The vehicle control device according to  claim 3 , wherein when a state in which the deviation is equal to or less than a predetermined value lasts for a predetermined period or longer after the correction is performed, the self-driving controller completes the correction. 
     
     
       5. The vehicle control device according to  claim 1 , wherein the calculator
 sets, as the index of the reference vehicle behavior, a position of the vehicle in a lane width direction that is estimated based on the target travel locus, and 
 sets, as the index of the actual vehicle behavior, an actual position of the vehicle in the lane width direction. 
 
     
     
       6. The vehicle control device according to  claim 5 , further comprising:
 a behavior controller configured to, upon detection of understeer behavior or oversteer behavior of the vehicle, perform behavior stabilization control to generate a difference in braking or driving force between a left wheel and a right wheel so as to generate a yaw moment to eliminate the understeer behavior or the oversteer behavior of the vehicle, wherein 
 the self-driving controller performs the correction after the behavior controller performs the behavior stabilization control. 
 
     
     
       7. The vehicle control device according to  claim 1 , further comprising:
 a behavior controller configured to, upon detection of understeer behavior or oversteer behavior of the vehicle, perform behavior stabilization control to generate a difference in braking or driving force between a left wheel and a right wheel so as to generate a yaw moment to eliminate the understeer behavior or the oversteer behavior of the vehicle, wherein 
 the self-driving controller performs the correction after the behavior controller performs the behavior stabilization control. 
 
     
     
       8. The vehicle control device according to  claim 1 , wherein when a state in which the deviation is equal to or less than a predetermined value lasts for a predetermined period or longer after the correction is performed, the self-driving controller completes the correction. 
     
     
       9. A vehicle control device to be installed in a vehicle, the vehicle control device comprising:
 a self-driving controller configured to 
 set a target vehicle speed and a target steering angle to allow the vehicle to trace a predetermined target travel locus, and 
 control the vehicle based on the target vehicle speed and the target steering angle; 
 a predictor configured to predict a vehicle behavior; 
 a calculator configured to calculate a deviation between an index of the predicted vehicle behavior and an index of a reference vehicle behavior; and 
 a detector configured to detect a turning state of the vehicle, 
 wherein the self-driving controller corrects one or both of the target vehicle speed and the target steering angle in accordance with an increase of the deviation, so as to stabilize the vehicle, and 
 wherein when completing the correction, the self-driving controller restores one or both of the target vehicle speed and the target steering angle to a value before the correction, using a low change speed relative to speed in normal time. 
 
     
     
       10. The vehicle control device according to  claim 9 , wherein the predictor predicts the vehicle behavior using a vehicle model of the vehicle, data of a road shape on which the vehicle travels, and an estimated friction coefficient of a road surface. 
     
     
       11. A vehicle control device to be installed in a vehicle, the vehicle control device comprising:
 a self-driving controller configured to
 set a first target vehicle speed and a first target steering angle to allow the vehicle to trace a predetermined target travel locus, and 
 perform a first self-driving control to control the vehicle based on the first target vehicle speed and the first target steering angle; 
 
 a calculator configured to calculate a deviation between an index of an actual vehicle behavior of the vehicle and an index of a reference vehicle behavior of the vehicle; and 
 a behavior controller configured to, upon detection of understeer behavior or oversteer behavior of the vehicle based on the calculated deviation, perform behavior stabilization control to generate a yaw moment to prevent the detected oversteer behavior or understeer behavior of the vehicle from continuing, 
 wherein the self-driving controller is further configured to
 when the behavior controller completes the behavior stabilization control during the first self-driving control, seta second target vehicle speed and a second target steering, 
 perform a second self-driving control to control the vehicle based on the second target vehicle speed and the second target steering angle so that the vehicle continues to trace the predetermined target travel locus from a first timing at which the behavior stabilization control completes to a second timing at which the calculated deviation is determined to be equal to or less than a predetermined first threshold for a predetermined period, and 
 upon determining that the calculated deviation is equal to or less than the predetermined first threshold for the predetermined period, resume the first self-driving control, 
 
 wherein the self-driving controller i) sets the second target vehicle speed to be lower than the first target vehicle speed and to be equal to or lower than an actual vehicle speed at the first timing based on the predetermined target travel locus and ii) sets the second target steering angle based on the predetermined target travel locus and the second target vehicle speed, 
 set the second target vehicle speed to be equal to the actual vehicle speed at the first timing, 1) when an absolute value of the deviation at the first timing is greater than a predetermined second threshold and a gradient of change of the absolute value of the deviation at the first timing is less than a predetermined negative third threshold, or 2) when the absolute value of the deviation at the first timing is equal to or less than the predetermined second threshold and the gradient of change of the absolute value of the deviation at the first timing is equal to or greater than the predetermined negative third threshold and is equal to or less than a predetermined positive fourth threshold, and 
 set the second target vehicle speed lower than the actual vehicle speed at the first time point, 1) when the absolute value of the deviation at the first timing is greater than the predetermined second threshold and the gradient of change of the absolute value of the deviation at the first timing is equal to or greater than the predetermined negative third threshold, or 2) when the absolute value of the deviation at the first timing is equal to or less than the predetermined second threshold and the gradient of change of the absolute value of the deviation at the first timing is less than the predetermined negative third threshold or is greater than the predetermined positive fourth threshold. 
 
     
     
       12. The vehicle control device according to  claim 11 , wherein the calculator
 sets, as the index of the reference vehicle behavior, a yaw rate calculated based on the first target vehicle speed and the first target steering angle, and 
 sets an actual yaw rate of the vehicle as the index of the actual vehicle behavior. 
 
     
     
       13. The vehicle control device according to  claim 11 , wherein the behavior controller configured to perform the behavior stabilization control to generate a difference in braking or driving force between a left wheel and a right wheel so as to generate the yaw moment to eliminate the understeer behavior or the oversteer behavior of the vehicle.